Potentially excessive follow-up blood cultures in Staphylococcus aureus bacteremia: opportunities for diagnostic stewardship
Iris D N Van Bommel, Nienke L Plantinga, Maaike S M Van Mourik, Hanneke Boon, Stefan M T Vestjens, Marjolein P M HensgensAbstract
Background
Follow-up blood cultures are recommended in Staphylococcus aureus bacteremia (SAB) to document clearance, but excessive culturing increases patient burden and healthcare costs. Guidelines advise repeat cultures every 2-4 days after initiation of antibiotic treatment. We quantified follow-up blood culture practices and evaluated opportunities for diagnostic stewardship.
Methods
We conducted a retrospective cohort study of adult SAB patients between 1 January 2014 and 1 January 2024 in three Dutch hospitals. A SAB episode comprised 30 days after the index culture and included a diagnostic period (≤2 days) and follow-up period (>2 days). Diagnostic stewardship opportunities during follow-up were defined as: daily culturing, obtaining >2 sets per day, or continued culturing after clearance.
Results
We identified 2499 SAB episodes among 2400 patients (median age 71 years, 36.8% female). Overall, 21014 blood culture sets were obtained, of which 12701 (60.4%) during follow-up. Follow-up cultures were performed in 83.4% of episodes. Among 6044 follow-up intervals, 3869 (64.0%) reflected daily culturing. Of 8037 follow-up culturing days, 302 (3.8%) had >2 sets per day. Among 1993 episodes with ≥1 negative culture, culturing continued beyond clearance in 903 (45.3%). Overall, 6432 of 12701 (50.6%) follow-up sets met ≥1 stewardship criterion; this proportion was higher in patients with endocarditis than in those without endocarditis in Hospital A.
Conclusions
Follow-up blood cultures in SAB frequently exceeded guideline recommendations. Limiting follow-up to 2 blood culture sets every 2 days until clearance is an important opportunity for diagnostic stewardship, while more intensive culturing may be clinically indicated in selected patients.